A lot of people are saying that you can take and hold a location if you have enough people, which is, of course a fair enough comment and for the first few weeks i'm sure it'd work well.
HOWEVER, think long and hard about how many people you allow to know about your prepping and objectives, only tell those you trust, you WILL have to make many tough choices.
The reason i say these 'lovely' things are of course the fact that we live in a very dependable world, which 98% of us are supported by just the 2%. And of course we are on an island, which means, we are doubley screwed. We have NO official food reserves, the food on the shop shelves and in the distribution centres are all we have.
For most of us our retreats are miles and miles outside of the local populus (Of Course!) which means a lot of travel, if you are truely looking at serious prepping, i pray that you can make the right balance between charity and survivability.
Rant over